This is a renewal application from Columbia University that requests funding for postdoctoral training program in digestive and liver diseases. The program is designed to train M.D. investigators to become independent basic, clinical and translational researchers. The program has been in existence for four years and to date has been highly successful in its mission. The training program has been focused initially on training adult gastroenterologists, but now seeks to expand to include a rapidly growing pediatric GI division. Both divisions now put a primary emphasis on research training in both the selection and training of their fellows. The program faculty, while drawing primarily from adult and pediatric GI divisions, now includes faculty from many departments. Trainees are assigned to a mentor in basic or clinical epidemiology research, and are given a specific research project, but also complete a rigorous program of didactic instruction that includes cross training and multidisciplinary educaiton. All trainees will be exposed to basic laboratory investigation and receive training in biostatistics and clinical trial design. This NIH training program builds upon very strong and academic fellowships in pediatric and adult GI, which are now developing many young academic faculty in these disciplines. Dr. Timothy C. Wang is the PI and Director of this training program, but ably assisted by Associate Directors Drs. Joel Lavine and Howard Worman. All three program leaders have actively mentored young basic and clinical scientists for many years, and have superb track records in training. The program is supported by both Internal and External Advisory Committees, and is tightly integrated with the Columbia University CTSA and MS/POR training programs.Strong emphasis is given to the recruitment of underrepresented ethnic groups and to training in ethical and responsible conduct.